1. Field of the Invention
The present invention relates to the field of a control system for the light emitting diode (LED) driving circuit, in particular with respect to a control system for the feedback controlled LED driving circuit.
2. Description of the Related Art
Recently, as the unceasing improvement in DC conversion driver technique used in light emitting diode (LED), such as various designs of linear electric power driver and switching power driver, and switching power driver comprises isolated, non-isolated and various derivatives of topology configurations of which aims at providing acceptable technical solutions to consumers in the fields of power factor, efficiency, power supply controller, light source flicker, dimming, safety regulation and cost and so on.
In terms of conventional LED driver circuit, the main problem of power supply controller lies in that it is self-powered which leads to that a transformer has to coil additional wires, slower start speed and false start resulted from current leakage of power switch may be also included. And the means of non-self-powered uses line voltage to directly reduce voltage for supplying power which wastes more electric power as well as degrades the entire conversion efficiency. In addition, regarding the conventional power factor correction (PFC), it mostly uses the waveform of AC voltage derived from analog conversion to correct the reference voltage, but the means is incapable of optimizing the power factor and current harmonics based on the adjusted current waveform adapted by various driving methods, and it also has to add extra pin to detect waveform and therefore raises the cost of controller.